Identification of irradiated food by thermoluminescence method

The purpose of this study is to give general and technical information about food irradiation and the detection of irradiated food by thermoluminescence technique (TL). Two types of dried legumes were used to identify the irradiated and unirradiated foods by TL technique. These spices are corn and chickpea which were packed in polyethylene bags and irradiated using a 60Co source with dose of 1, 4, 8, 10 kGy, respectively, with a dose rate of ?1kGy/h. The TL method requires that the inorganic components be separated from the samples. Separation of the organic and inorganic phases was made by using a chemical method. Then, the samples were dried and stored at room temperature in dark region. TL measurement was carried out using a TL reader at a heating rate 1 0C/sec between room temperature and 4000C. The light emission was recorded in a temperature-dependent mode as a glow curve and was measured in units of nano coulombs (nC). It was observed that the extracted samples from both legumes exhibit good TL Intensity and the TL intensity of glow curves of them increased proportionally to irradiation doses. Maximum TL temperatures of all irradiated samples are found to be between the 250-280 oC temperature intervals, it was also found that unirradiated samples did not exhibit any glow peaks. Key Words: Food irradiation, thermoluminescence, TL measurement, glow curve.